We have begun building the retaining wall between the swimming zone and the planted regeneration (natural filter) zone:

Building the retaining wall

To the right of the wall is the regeneration zone. To the left is the swimming zone. The large PVC pipe is part of the water circulation system. If you imagine gravel and then sand covering the pipe with plants planted into the sand, the water will filter down through the plant roots, sand, and then gravel until it enters one of many small holes drilled into the pipe.

The water then flows through the pipe to a cistern where it is pumped back into the swimming zone:

You can see the cement cistern at the end of the pipe in the upper left of this photo.

We’ve slowly begun washing gravel and sand and you can see it beginning to be laid down near the pipe on the right. Washing it is turning into quite a laborious process, so we are looking for better ways to automate this. (We are in the rainy season now, so the gravel and sand also help people to move around when the ground gets muddy.)

Here is a wider view from the other side:

In the foreground is a second smaller regeneration zone, and you can see the white line which is the cement support structure for another retaining wall. There will be another pipe that will run out along the right side to the cement cistern over there.

With the rain water building up and the water still looking quite clear, I’m already wishing I could take a swim. 🙂